Announcement

Collapse
No announcement yet.

Corretto Improvements

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Corretto Improvements

    Hi everyone,

    For those that have been following the roaster thread you may have seen some of my posts re Corretto set up.

    On 1st November I showed a simple way to reduce chaff and heat being drawn back into the HG, follow this link for photo. http://coffeesnobs.com.au/YaBB.pl?num=1154442377/144#144

    After thinking for a while , it occurred to me that most of the heat produced is blown straight out the top of the bin, unlike in the proprietary machines like the GC or Hottop, where the heat is channeled through the body and out through a filter arrangement.

    What all this means is that a HG must produce more heat (a problem with smaller capacity HGs) than is really required to complete the roast, this must shorten the life of the HG and can produce a patchy roast.

    What I have come up with is the most basic of modifications as seen in the picture all I have done is cut a vent plate (lid) out of sheet aluminium, this does several things:

    a) reduces heat input......... I am now roasting at approx 310c at the nozzle, previously approx 380c
    b) My HG Makita thermocouple is now set to 3 -3.5 (half power) previously 4.5 - 5, this obviously has less stain on the HG
    c) No need to adjust the height of the HG as temp control can be made using the vent plate
    d) Shorter roast times as there is less heat loss
    e) more even roasts

    The HG nozzle is just inside the bin, the plate is cut to fit around and slides about the top of the bin, you need pliers or gloves to move the plate as it gets very hot.

    By moving the vent plate during the roast temp is easily varied, you can still see the beans, chaff and heat are further directed away from HG inlet, I do still have a fan blowing though.

    My two latest roasts are a Peru Grace Villa and an Indian Chikmagalur, both took about 20% less time to roast, coloured up nicely to CS 9 - 10, just on first snaps SC and are superior to previous roasts.

    So Corretto roasters give it a go and see if your own roasts improve, then post your results for us all to see.

    Cheers Gazz


  • #2
    Re: Corretto Improvements

    Good work Gaz I will give it a try, would the harder African bean roasts be affected by the shorter roast times?

    Comment


    • #3
      Re: Corretto Improvements

      Brilliant idea! I gotta try this as Im having some issues trying to control the rate of rise of temps with the current setup with fixed height/ var temp HG as well as fixed temp/ adjustable height and a BM that terminates the knead cycle after 24 minutes (although instruction book says 26 minutes).

      Comment


      • #4
        Re: Corretto Improvements

        Originally posted by greenman link=1200789910/0#1 date=1200791576
        Good work Gaz I will give it a try, would the harder African bean roasts be affected by the shorter roast times?
        I dont think so as there is more retained heat in the bin which seems to give a more stable temp in the bean mass, temp ramping has a more linear increase as well.

        My last Peru GV roast dropped from 16 mins to just over 13 mins for 300gm

        the main thing is that there is less stress on the HG to produce max heat for a long period.

        Gazz



        Comment


        • #5
          Re: Corretto Improvements

          PS to above

          First C at 9.30mins @ 214c SC 13.20mins @ 230c

          These crack temps are the same as my previous roasts

          pulled just on SC starting , finished colour CS 9

          Start 300gm finish weight 245gm

          Taste after 48 hrs ab fab

          Gazz

          Comment


          • #6
            Re: Corretto Improvements


            Id be a bit cautious of making the roast too quick there Gazz. The end result could be a popper style roast with the beans becoming quite bright and possibly bitter.

            Another issue is visibility. With the aluminium lid over the top of the bowl it must be hard to see and judge the roast.

            Kind of reminds me of a similar mod I did way back ...........
            http://coffeesnobs.com.au/YaBB.pl?num=1154442377/106#106

            I found this was only needed on freezing cold days or extremely windy days. I dont much bother with it now, but can come in handy as previously mentioned.

            Anyway, its fun to play


            Belinda

            Comment


            • #7
              Re: Corretto Improvements

              Originally posted by Corretto link=1200789910/0#5 date=1200802316
              Id be a bit cautious of making the roast too quick there Gazz. The end result could be a popper style roast with the beans becoming quite bright and possibly bitter.

              Anyway, its fun to play

              Belinda

              Points well taken Belinda.

              However I did not mean that by covering the pan in such a way that the cover becomes a tight fitting lid, judicious use to control temp ramping and heat retention with less heat input is what I seem to have achieved, where as in some circumstances ie windy or lower power HGs the cover has some benefited the roast by not having a really long roast time, which can be as bad as too short a roast time.

              I really only have the cover on about 70% of the bin so can still watch (get mesmerized) as the beans go round.

              Also it eliminates the need for raising or lowering the HG.

              I suppose my post was meant to stimulate other CSs into trying something different.

              As you say its fun to play

              Cheers Gazz

              Comment


              • #8
                Re: Corretto Improvements

                Regarding outside influences affecting the roast, when Perth had its heat wave and it was 44C I did a roast, it must have been 50-55C in my garage but being short on roasted beans I went ahead, got to first crack just before desired mark, I raised the gun but the roast went to second crack in just over 2 minutes and caught me by surprise, they have cupped ok so it wasnt a wasted effort.

                Comment


                • #9
                  Re: Corretto Improvements

                  Gazz,

                  How did you get the bean temperature? Where does the temperature sensor go in this case?
                  Do you just put it somewhere inside a bin?

                  Cheers,

                  Viktor

                  Comment


                  • #10
                    Re: Corretto Improvements

                    Hi Viktor

                    TC is in the bottom of the bin

                    A second TC is just under the HG nozzle

                    Follow this link for photos of my set up, also there is lots of info in the roasters section in the forum.

                    http://s216.photobucket.com/albums/cc28/Gazz51/Correto/

                    PM or email me if you need more specific info

                    Cheers Gazz

                    Comment

                    Working...
                    X